Ulmus 'Exoniensis'

Ulmus

Exeter Elm in Amsterdam
Cultivar 'Exoniensis'
Origin Exeter, England

Ulmus 'Exoniensis', the 'Exeter Elm', was discovered near Exeter, England, in 1826, and propagated by the Ford & Please nursery in that city.[1][2][3][4] [5] Traditionally believed to be a cultivar of the Wych Elm U. glabra, its fastigiate shape when young, upward-curving tracery, small samarae and leaves, late leaf-flush and late leaf-fall, taken with its south-west England provenance, suggest a link with the Cornish Elm, which shares these characteristics.

Description

The tree initially has an upright, columnar form,[6] but later develops a large rounded crown and occasionally reaches 17 m in height. It is chiefly distinguished by its contorted leaves, < 11 cm long by 8 cm broad, which occasionally wrap around the branchlets and remain thus well into winter.[7]

Pests and diseases

'Exoniensis' possesses a moderate resistance to Dutch elm disease, and consequently often featured in the Dutch elm breeding programme in association with the Field Elm U. minor and Himalayan Elm U. wallichiana.[8]

Cultivation

Once commonly planted in the UK and parts of western Europe, 'Exoniensis' is also known to have been marketed in Poland in the 19th century by the Ulrich nursery,[9] Warsaw, and remains in commerce there. In Sweden it is sometimes pruned from an early age to form a tidy cone-shaped tree called locally 'pyramidalm' (: pyramid elm).[10] It is found in Australia at the Ballarat Botanical Gardens where it is listed on the Significant Tree Register of the National Trust, but is not known to have been introduced to North America.

Notable trees

A 180-year-old specimen in Hamburg has attained a height of 28 m and a trunk diameter of 1.45 m.[11] The UK TROBI Champion tree is in Scotland, at Baxter Gardens, Dundee, measuring 15 m high by 103 cm d.b.h. in 2004.[12] The cultivar is represented in Éire by a tree at Birr Castle (Mount Palmer), County Offaly, with a d.b.h. of 29 cm when measured in 2002.

Hybrid cultivars

'Clusius', 'Columella, 'Dodoens', 'Lobel', 'Plantyn', 'Nanguen' = Lutèce™, 'Wanoux' = Vada™.

'Exoniensis' also indirectly featured in the Italian elm breeding programme as an ancestor of 'Plantyn', which was commonly crossed with clones of the Siberian Elm Ulmus pumila to produce the cultivars 'Arno', 'Plinio', and 'San Zanobi'.[13][14]

Synonymy

Accessions

Europe
Australasia

Nurseries

Europe

References

  1. ↑ Bean, W. J. (1981). Trees and shrubs hardy in Great Britain, 7th edition. Murray, London
  2. ↑ Elwes, H. J. & Henry, A. (1913). The Trees of Great Britain & Ireland. Vol. VII. 1848–1929. Private publication, Edinburgh. Republished by Cambridge University Press, 2014.
  3. ↑ Richens, R. H. (1983). Elm. Cambridge University Press.
  4. ↑ White, J. & More, D. (2003). Trees of Britain and Northern Europe. Cassell's, London.
  5. ↑ Harvey, J. (1974). Early Nurserymen.  p.104. Phillimore & Co. Ltd. 1975. ISBN 978-0850331929
  6. ↑ Photograph of fastigiate form of young Exeter elm
  7. ↑ Photograph of 'Exoniensis' leaves in early summer
  8. ↑ Heybroek, H. (1983). The Dutch elm breeding program. In Sticklen & Sherald (Eds). Dutch elm disease research (Ch. 3). Springer Verlag, New York.
  9. ↑ Ulrich, C. (1894), Katalog Drzew i Krezewow, C. Ulrich, Rok 1893–94, Warszawa
  10. ↑ Photographs of 'Pyramidalm' and unpruned 'Exoniensis' in Sweden, www.tradgardsakademin.se
  11. ↑ U. glabra 'Exoniensis', the "Planten un Blomen", Hamburg: from the Handbuch der Ulmengewächse,
  12. ↑ Johnson, O. (2011). Champion Trees of Britain & Ireland, p. 169. Kew Publishing, Kew, London. ISBN 9781842464526.
  13. ↑ Santini A., Fagnani A., Ferrini F. & Mittempergher L., (2002) 'San Zanobi' and 'Plinio' elm trees. HortScience 37(7): 1139–1141. 2002. American Society for Horticultural Science, Alexandria, VA 22314, USA.
  14. ↑ Santini A., Fagnani A., Ferrini F., Mittempergher L., Brunetti M., Crivellaro A., Macchioni N., Elm breeding for DED resistance, the Italian clones and their wood properties. Invest Agrar: Sist. Recur. For. (2004) 13 (1), 179–184. 2004
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